Forty-seven nonmelancholic depressed outpatients were infused with sodium lactate to explore the relationship between history of panic attacks and lactate-induced panic. Lactate panic was rated without knowledge of history of panic. Fifteen of 29 patients (52%) with a history of spontaneous panic experienced panic attacks in response to lactate. Only 1 of 18 patients (6%) without a history of spontaneous panic experienced a lactate-induced panic attack--a highly significant difference. The likelihood of lactate panic was related to frequency of spontaneous panic attacks. The implications of these findings for understanding the relationship of panic attacks and depression are discussed.